Generally, a wireless communication network can simultaneously support communication for multiple wireless communication devices, also referred to in the state of the art as terminals or as user equipments (UEs). Each wireless communication device communicates with one or more network access nodes, e.g. a base station such as a Node B or an Enhanced Node B (EnodeBs or eNB), via a downlink (from the network access node to the wireless communication device) and/or uplink (from the wireless communication device to the network access node) transmission.
The next generation radio communication system, i.e. the fifth generation (5G), takes it even one step further by connecting all sorts of devices and machines. A wireless communication device may thus for example be an user equipment (UE), a mobile phone, a smartphone, a data modem, a mobile computer, a vehicle, a device of industrial automation, such as a sensor, an actuator or a controller.
One key objective of 5G radio technology is to support highly reliable ultra-low delay machine-type communication (MTC). Thus industrial applications are a typical use cases for wireless communication devices. Wireless communication may be used for remote control of heavy machinery in remote locations or hazardous places; for monitoring and control of smart grids or industrial applications in general.
In order to access a wireless communication network, e.g. via a network access node, an access procedure may be used in a contention-based or a contention-free manner.
In contention-based access, a wireless communication device may select a signature at random, at the risk of “collision” at the network access node if two or more wireless communication devices select the same signature. Contention-free access avoids collision, by informing each wireless communication device which signature it may use. Such access methods are for instance described in international patent application publication WO 2015/071000 A1.
Further on, it has become known from US patent application publication US 2012/0044816 A1 to make use of a contention-based access configuration via physical downlink control channel signaling. Accordingly, configuration data sent to the user equipment devices identifies multiple contention-based access zones, along with minimum power headroom values for each contention-based access zone. A probability factor may also be used to lower collision possibility by influencing whether the user equipments perform contention-based uplink access.